This document has been approved for publication by the Management Council of theConsultative Committee for Space Data Systems (CCSDS) and represents the consensustechnical agreement of the participating CCSDS Member Agencies. The procedure for reviewand authorization of CCSDS documents is detailed in theProcedures Manual for theConsultative Committee for Space Data Systems.

This document is published and maintained by:

CCSDS Secretariat

Space Communications and Navigation Office, 7L70

Space Operations Mission Directorate

Washington, DC 20546, USA

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

FOREWORD

This document is a CCSDS Informational Report, which containsagencyUse Case material

Through the process of normal evolution, it is expected that expansion, deletion, or modificationto this Report may occur.This Report is therefore subject to CCSDS document management andchange control procedures, which are defined in reference [17]. Current versions of CCSDSdocuments are maintained at the CCSDS Web site:

http://www.ccsds.org/

Questions relating to the contents or status of this report should be addressed to the CCSDSSecretariat at the address on page i.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

At time of publication, the active Member and Observer Agencies of the CCSDS were:

Member Agencies

–

Agenzia Spaziale Italiana (ASI)/Italy.

–

British National Space Centre (BNSC)/United Kingdom.

–

Canadian Space Agency (CSA)/Canada.

–

Centre National d’Etudes Spatiales (CNES)/France.

–

Deutsches Zentrum für Luft-

und Raumfahrt e.V.(DLR)/Germany.

–

European Space Agency (ESA)/Europe.

–

Federal Space Agency (Roskosmos)/Russian Federation.

–

Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.

–

Japan Aerospace Exploration Agency (JAXA)/Japan.

–

National Aeronautics and Space Administration (NASA)/USA.

Observer Agencies

–

Austrian Space Agency (ASA)/Austria.

–

Belgian Federal Science Policy Office (BFSPO)/Belgium.

–

Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.

National Institute of Information and Communications Technology (NICT)/Japan.

–

National Oceanic & Atmospheric Administration (NOAA)/USA.

–

National Space Organization (NSPO)/Taipei.

–

Space and Upper Atmosphere Research Commission (SUPARCO)/Pakistan.

–

Swedish Space Corporation (SSC)/Sweden.

–

United States Geological Survey (USGS)/USA.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

PREFACE

This document is a draft CCSDStechnical information reference pertaining to wireless networkingtechnologies. Its draft status indicates that the CCSDS believes the document to be technicallymature and has released it for formal review by appropriate technical organizations. As such, itstechnical contents are not stable, and several iterations of it may occur in response to commentsreceived during the review process.

Implementers are cautionednot

to fabricate any final equipment in accordance with thisdocument’s technical content.

NOTE:

Inclusion of any specific wireless technology does not constitute any endorsement,expressed or implied, by the authors of this Green Book or the agencies that supported thecomposition of this Green Book.

Description: RFID technology facilitates part tracking and inventory management. Use of RFIDin commercial and DoD sectors continues to increase for supply logistics. NASA bond roomscould replace existing paper tags with RFID tags. Tags are typically verified during or after tagattachment. Standards-based interrogators and tags permits read of vendor tag information so thatpart heritage is not lost. Advanced concepts,such as part environmental exposure history (e.g.,shock or thermal extremes) are also possible.

Special considerations: Should be coordinated with Logistics and Maintenance andInteroperability SIGs. Reference proposed amendment {(Jimmy Miller, MSFC) toConstellationOperations Concept (CxP70007)} : “All flight hardware (at the LRU level) employs a commonscheme of identification marking (such as RFID) to assure accuracy and standardization ofidentifying as built and as flown configuration.”

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DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.1.2

VEHICAL SUPPLY TRANSFERS

Figure1-2:RFID vehicle supply transfers concept.

Objective: Accurate verification of

supply transfers from any supply element to any vehicle.

Description: Ingress and egress of supplies are tracked into and out of any vehicle. RFIDInterrogation is portal-based, and auxiliary portal sensors determine direction of tag. Items aretransferred in various forms {e.g., equipment, spares, LRUs, Cargo or Crew Transfer Bags(CTB), etc.} Early application opportunity exists for supply of the CEV Orion (see CEV stowageconcept in Appendix D–

NASA only). ROI for RFID-based inventory management on CEV isquestionable since the vehicle will not be re-supplied. However, RFID application in trackingsupplies to and from the vehicle is considered of significant benefit. Interrogated items willpresent a variety of material parameters to the interrogator.Cost for high performance tagantennas, to assure near 100% read rates, if required, is likely to be offset by labor savings fromreduced ground support and crew time.

Initial ground-based assessment of crew-assisted, SAW-based RFID for item-level interrogationindicated 30-40 seconds per CTB, compared to over 10 minutes per CTB using an opticalbarcode scanner when reading all items in the bag.

Enhanced passive RFID tags are positioned as panels at the Landing site.

–

Interrogator beam-steering is not required.

–

Requires extended range RFID tags.

–

Low TRL: Has not been tested.

1.1.14

SMART CONTAINERS

Description:Smart containerslocally store data about the contents. This is a use-case that can revealvery useful, but is dependent on the amount of data that can be stored.

1.1.15

RFID ENHANCED TORQUE

SPANNER

Description:A bolt contains the recorded data (e.g. angle, date, torque) of a screwed joint. With anelectronic torque wrench equipped with an RFID reader, the wrench could discover the requiredsettings and could adjust itself automatically.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

Figure1-11:RFID torque spanner.

1.1.16

RFID ENHANCED BOLT IDENTIFICATION

Description:During fastening of a bolt, an ultrasonic wave technology is used to measure itselongation. To be achievable, the bolt must be identifiable and the

calibration data must beacquirable. Current procedures use barcode for bolt identification and a database for the related data.RFID would permit to locally store the ID and the required calibration data directly on the bolt.

Figure1-12:RFID bolt identification.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.1.17

TECHNICAL CHECKS

Description:Using RFID tags fixed on checkpoints can enhance the accomplishment of technicalchecks. The check is automatically logged, identification of checkpoints is eased and additional datacan be supplied to the personnel. RFID-tags with analogue or digital inputs can supply furtherinformation e.g. on pressure, crack propagation and more.

1.1.18

RFID ENHANCED CONNECTORS

Description:RFID is used to insure that a connector is connected to the correct slot. The connectorhas

an RFID tag, the technician queries the tag with a pen-like, millimetre range reader and theconfiguration gets verified.

Figure1-13:RFID enhanced connectors.

1.1.19

BATTERY MANAGEMENT

Description:Storing life data on batteries can simplify and ease battery management. The usage ofpartly loaded or over aged batteries for experiments and tools can be avoided e.g. on a space station.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.1.20

DEEP FREEZER SAMPLES

Description:RFID could be used to manage the samples stored in the deep freezer device on theISS.Barcodes are inappropriate due to the frosting and readability problems.

Figure1-14:MELFI cooling system onboard the ISS.

1.1.21

RFID ENHANCED PIPEFITTING

Description:Pipetting is a common task related to biological experiments. RFID can be used toavoid errors.

1.1.22

SENSOR TAGS ASSISTED

TESTING

Description:This application uses the RFID technology to transmit analogue signals liketemperatures or acceleration data from a tested structure to a base station. The advantage is that thesensor does not have a battery and its data is retrieved on demand.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2

INTRA-VEHICLE WIRELESS APPLICATIONS

These use-cases do not specify a specific technology or frequency and therefore do not coverissues like electromagnetic compatibility.

1.2.1

CONTROL OF ROBOTIC AGENTS AROUND THE ISS

Figure1-15:Control of robotic agents.

Objective:

Give robotic agents the appropriate freedom to move around the ISS while beingcontrolled and transfer data wirelessly.

Description:

Robots like ESA’s Eurobot are designed to execute tasks outside the internationalspace station. They are self-powered, mobile entities required to transmit Real-time video datawhile being controlled by astronauts within the station

or ground personnel. In the special case ofthe Eurobot, itshall not have any umbilical

cable connections to the Home-Base.

Wireless dataconnection is therefore necessary and the chosen technology must offer enough flexible to insurethe communication while the robotic agent moves around the ISS. The complex architecture ofthe ISS requires

that several wireless access points are used in a complementary scheme to offera global coverage around its structure.

Range:

20m

Data rate:

High

Availability:

High

Criticality:

Medium

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.2

SPACECRAFT HEALTH SENSORS

Figure1-16:Spacecraft health assessment.

Objective:There are several objectives when using wireless sensors within spacecraft:



Reduce number of sensors by exploiting redundancy advantage of wireless networks



Reduce the time required for assembling, integrating and testing several hundreds ofsensors by removing their harness (considering self-powered sensors)



Increase the flexibility regarding late-changes in requirements

Description:

During the past years, wireless sensor networking has made tremendous progresses in regard torobustness, power consumption and flexibility which led the ESA and other agencies to study thepossibility of using the technology within spacecraft. The general results are a significantreduction of AIT efforts and time and a new redundancy scheme for no

gain in mass. Generallyspeaking, the implied low data rate allows great receiver sensitivity and therefore a lowtransmitted power. The NASA has already flown wireless sensors onboard the wings of the spaceshuttle (Invocon).

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.3

WIRELESS SUN SENSORS

Figure1-17:Wireless sun sensors.

Objective:

Free self-powered sun sensors fromcomplex and unnecessaryharness

Description:Sun sensors obtain enough energy from the sun to be self-powered. The onlyremaining cabling is the data link. Integrating a wireless

interface to a self powered sun sensorincreases the system flexibility and decreases the design and integration effort. Autonomouswireless sun sensors have been flown in the past with great success (e.g. Delft University ofTechnology). The use of sucha sensor requires the spacecraft to have a wireless interface tocommunicate with it in a star-like topology.

Range:

2m

Data rate:

Low

Availability:

High

Criticality:

High

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.4

ROTARY MECHANISMS AND FOLDABLE STRUCTURES

Figure1-18:Wireless mechanical components.

Objective:To reduce the complexity of rotating and foldable mechanisms and to offer infiniterotation capability.

Description:Any transmission between two parts in movement will generate problems withwires. This problem increases when the number of cycles is high or when the rotating angle islarge, which force the designers to have a margin factor as high as 1.5 to 3. Wireless links willhave no wear out, infinite rotation capability, no life time qualification tests and lower costs.Another example of application would be the energy storage in kinetic momentum.

Range:

20cm

Data rate:

Low to high

Availability:

High

Criticality:

High

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.5

SEPARATION OF MODULES

Figure1-19:Inter-vehicle wireless communications.

Objective:

Create a data connection link between modules that separate (e.g. rover and lander)

Description:There are several sub-types of this use-case, one of them being the interconnectionbetween a lander and its hosted rover. In the specific case of ESA’s ExoMars, the rover haspower and data lines connected to the lander, this being the only way for the rover to use thesolar panels of the transfer vehicle during the space travel phase. At separation, the wires are cutthrough a thermal process which induces very high disturbances (e.g. changes in impedance) inthe communication bus, therefore requiring the use of higher margins and special dispositions.

The connection of the two data handling systems through a wireless link would simplify theseparation process and its related risks on the communication bus, while still allowing the healthmonitoring of the rover during the space traveling phase.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.6

ACCESS POINT ON LAUNCHERS

Figure1-20:Wireless access for launcher payloads.

Objective:Provide an untethered

data link between the launcher payload (satellite) and thelauncher data handling system andprovide a monitoring facility to the satellites during the launch(thermal, mechanical, vibration...).

Description: A

wireless access point on a launcher offers the satellite the possibility to transmitinternal monitoring data to the ground without the physical wired bound to the launcher. Thelauncher shares its data handling system through this interface and simplifies the integration ofthe payload within the fairing while reducing the risks of failure at separation. This scenariorequires that the satellite has a wireless interface to its data handling system as well as acompatible communication protocol that can forward the satellite health data to the ground

station.

Range:

2m

Data rate:

Medium

Availability:

Medium

Criticality:

Low

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.7

NETWORK OF SENSORS ON LAUNCHER

Figure1-21:Launcher and harness mass reduction.

Objective:Harness and launcher mass reduction.

Description:

There are several dozens of sensors onboard launchers that are wired to thelauncher data handling bus. For some types of sensor networks used by launchers, the reliabilityis not stringent (10-4) but the availability is very important for the telemetry system. Launchersare between 30 and 60 meters tall which results in long data cables. In the current wiredarchitecture, precautions in the form of bonding and shielding have to be taken in order to

The short mission time oflauncher makes the wireless alternative advantageous in regard to the low-capacity, low-weightbatteries that can be used to power thewireless interfaces and sensors.

Range:

3m

Data rate:

Medium

Availability:

High

Criticality:

Low

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.8

SPACECRAFT BUS

Figure1-22:Harness complexity, volume and mass reduction.

Objective:Reduce

the harness complexity, volume and mass.

Description:Data harnessing substitution with wireless technologies is an alternative to thecurrently wired spacecraft buses like Mil1553 and CAN. The foreseen advantages are reducedAIT time, a reduction in wiring volume, mass and complexity. Even thought radio

frequenciescould be suitable, optical technologies are preferred for such a type of applications due to theabsence of electromagnetic compatibility issues.

With the support of the European Space Agency, INTA (Spanish National Institute of AerospaceTechnology) has successfully flown in 2007 a wireless optical communication system betweenpayloads onboard a Foton capsule. The same team has also scheduled the flight of a CAN busover optical link. They have also built a Mil-1553 bus over optical links.

Range:

3m

Data rate:

Medium to High

Availability:

High

Criticality:

High

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.9

SCIENTIFIC INSTRUMENTATION WITHIN HEAT SHIELDS

Figure1-23:Science instrumentation mass reduction.

Objective:Reduce the mass of the heat shield’s science instrumentation

harness, the related AITtime and the risks of the shield separation process.

Description:

The heat shields of atmospheric reentry vehicles has been carefully studied andmodeled for several decades and permit efficient energy dissipation during the breaking phase inthe atmosphere. Contrary to the general perception, there is little empirical environmental data ofthe heat shield locality for the descent phase. Models have been developed and validated duringcontrolled tests on Earth, but the difficulties

implied by the separation of the heat shield from themain vehicle and its corresponding safety issues have limited the deployment of sufficientinstrumentation within the shield itself. Typical instrumentation being mainly made of cablesconnected to thermocouples, thermistors, pressure sensors and to the vehicle’s power source,these direct connections to the main vehicle induce a supplementary risk of separation failure,leading to the reluctance of integrating such instruments. This lack of sufficientand accurateempirical data pushes the spacecraft designers to increase the margins of safety, consequentlyincreasing the heat shield mass.

While wireless communication already solves the intrinsicproblem of direct cable connection between the shields and the vehicle and its related safetyissues, it isbelieved

that wireless sensor nodes replacing the many instrumentation cables mayhave a considerable mass advantage over a cabled solution.

Range:

2m

Data rate:

Low

Availability:

Medium

Criticality:

Low

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.10

PLANETARY SURFACE EXPLORATION

Planetary surface exploration is a key goal for several Agencies and offers a great deal of sciencereturn. For a short or medium range (hundreds to thousands of meters), self-powered wirelesspayloads are considered

as an extension of the master spacecraft (e.g. lander), therefore justifyingtheir pertinence in the intra-spacecraft class of wireless use-cases. Most of the following use-cases are based on a lander-payload scheme, where the payload is made of one or several scienceinstruments connected to the lander/rover through a wireless network of sensors.

Description:During the descent, probes could be released and create a mesh network to relay thedata to the lander/rover. Meteorological and geological units would transmit, on a periodicalbasis, parameters like atmospheric pressure, temperature, wind speed, humidity, light intensityand soils constituents.

Range:

~500m between nodes

Data rate:

Low

Availability:

Low

Criticality:

Low

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.2.10.2

Seismology package

Source: Systems Engineering & Assessment Ltd

Figure1-26:Planetary surface seismology data.

Objective:From deployed sensors, acquire seismological data in the locality of a lander or othersurface base

Description:Study of the seismological behavior of planetary bodies might generate veryvaluable science data and an understanding of the current activity of its core. The total coveragerequired may be as little as 5km, but the two most critical parameters are the accurate timing andthe known position of the nodes.

Reduce the necessary EGSE modifications due to changes in spacecraftconnections



Simplification and improvement the spacecraft access during thermal vacuum.

Description:

The ESA and other agencies have shown great interest in new possibilities tosimplify the EGSE within clean chambers. Such a solution is foreseen to reduce the complexityof the equipments, to reduce the mass and volume of the onboard connectors (converted into awireless node) and to simplify the test procedures which will then allow saving time and costs.

ESA wireless technology dossier and the CCSDS wireless ‘bird of feather’ identified lowpower proximity wireless sensor networks as an application area to promote prior to anycommand and control wireless applications.

Europeanspaceprime industries

consider

as welllow power wireless sensor networks as an area where the potential mass and power gain, as wellas the resulting flexibility in the conception, assembly and testing of the spacecraft are ofpotential high interest.

These simple sensors can cover a wide range of applications, as shown inFigure 4-1: fromsimple functionssuchas sun sensors to thermal control interfaces. The standardization effort onthese discrete interfaces is part of ESA strategy.

In the context of spacecraft architecture optimization, the focus is often made on these discreteinterfaces commonly used in a spacecraft, which, because they are point to point interfaces, areconsidered to be possibly optimized if replaced bya network configuration, the optimizationbeing even more relevantfor a wireless network.

If

wireless sensors are used, the harness neededfor interconnecting the sensors togetherand/orwith the on board computer can be entirelyremoved (provided that the sensors are self powered) and the concept of sensors network isoptimized in terms of harness, butalso in terms of

spacecraft conception,

integration and testing.

Such use of wireless sensors has been identified as an Agency-relevant driving scenario by

ESAwhich

initiated a TRP study started in November 2007. This study concerns RF wireless intraspacecraft communications, focusing on low power proximity sensor networks based on 802.15.4and

The approximate size ofthewireless sensorsnetwork provides a sense of the potential complexity of the networktopology, and the resulting complexity faced by routing protocols.

The presence of several cavities within a spacecraft may require different network topologies toinsure the link budget in eachoneof the cavities, asshown

inFigures 4-2 and 4-3.

OBC

Wheels

GPS

CentralRFpoint

…

MIL-STD-1553 or other

SecondaryRF point

SecondaryRF point

SecondaryRF point

Power & data lines

Cavity 1

Cavity2

Cavity3

Cavity4

OBC

Wheels

GPS

CentralRFpoint

…

MIL-STD-1553 or other

Cavity 1

Cavity2

Cavity3

Cavity4

Low power sensor network using secondaryRF access points to the local RF wirelessnetworks

Low power sensor network using a single RFaccess point to the RF network

Figure1-32:Low power sensor network topologies

Traffic and flow diversity:

A low power proximity sensor network would need to transportonly one class of traffic,e.g.

sensor data. Greater traffic diversity may increase the need for thenetwork to provide QoS assurance to the different classes of traffic.

Battery power:

For local RF networks, self-powered sensors can be considered as promising.Self powered sensors allow the wireless sensors to be free from any power cables by embeddingtheir own power source to supply the sensor, the internal electronic and the radio device. Themain constraint is the life time of the battery directly dependent on the average consumption ofthe unit. Roughly, high data rate sensor will be usable only on short missions (launchers,vibration or shock monitoring, manned station with maintenance…)

while long mission ofseveral years will be reached only with ultra low consumption units needing a very limitednumber of transferred bits.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

Energy efficient protocols

&Power-aware routing algorithms:Highly efficient on the airmessage formats should be used to minimize the power consumed transmitting data over an RFlink. Where possible, compute cycles should be traded off against bits transmitting on the air.However, developing general rules for making these trades

is very difficult.

Moreover, it can beuseful in some cases for the network layer protocol to provide a facility to compress applicationdata(sensors transmitting a high amount of data…)

Electromagnetic compatibility:

The EMC compatibility between the low power sensorsnetwork and the spacecraft is a potential design constraint. Limited emission power is needed inorder not to disturb any unit

located inside the spacecraft.The

frequency band of the emittingsensors needs to meet the EMC requirements of the spacecraft.

Wireless sensors technology selection:

Many commercial of the shelf wireless standards andtechnologies are probably able to provide a technical answer to the wireless sensor bus conceptfor space. However, their enhancement is likely to be needed would it be only to stand the harshspace environment conditions. When choosing a wireless sensors technology, differentparameters can be traded off:

Current status of wireless technology:

Currently available technologies could avoid the risk oflengthy and expensive development programs. Several criteria can be considered whenevaluating the current state of the technologies requiredfor low power proximity sensornetworks: applicability, reliability, scalability (can support large networks with few significantchanges to the technologies), longevity, technology readiness level.The compliance tointernational standards insures interoperability of different sensor devices, and the long termavailability of wireless technology.

The conformance to space requirements or the upgradeabilityto space qualified components is an asset for space use.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

CREWED SPACECRAFT AND HABITATS

1.2.15.3

Lunar Habitat and Outpost

The evaluation of the wireless communications networks required to support manned operationsfor a lunar habitat serves to identify requirements and constrain available options. Figure 1shows the Shackleton Crater Rim Outpost location at the South Pole of the Moon. This potentialoutpost location site has several important properties: it is located at a pole–

so there’s anincreased probability of ice (either H20 or C02) available for in-situ resource utilization, there isample sunlight,

and scientifically intriguing geology and topography. Importantly, from acommunications standpoint, the outpost site will experience direct-to-Earth communication gapsof at least seven days. Hence, a Lunar Relay Satellite (LRS) will be required for Earthcommunications.

High-rate data communications to LRS and direct-to-earth when line-of-sight is available

4)

Video conferencing: voice and video delivery between crew members and from habitat-to-earth

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

5)

Crew member personal computing and entertainment devices

1.3

PLANETARY SURFACE COMMUNICATIONS

An over-arching design driver for the outpost communications infrastructure is that the surfacecommunications

assets are expected to be developed by independent international partners. Anoutcome of this expectation is thatplanetary surface

communication architectures will be drivenby the fact that there will be multiple Earth-based mission operations centersfor the differinginternational partners, and there will be multiple communications systems from different spaceagencies and commercial industries. The result is thatplanetary surface

communicationsarchitectures will be mission-operations focused, andthe constituent communications systemswill need to be both flexible and interoperable. In support of this observation, NASA hasspecified that its lunar communications architecture shall support IP-addressable endpoints, thuspotentially easing a transition to standards-based COTS products.

Figure4-5

depicts a candidate network topology for a lunar outpost utilizing a LunarCommunications Tower (LCT). The LCT functions as a basestation relay for externalcommunications within an external wireless wide-area (WWAN) network. Also depicted is asingle Lunar Relay Satellite (LRS). The LRS is used to relay habitat and surfacecommunications to Earth when a direct to earth (DTE) line of site to terrestrial receiving stationsdoes not exist from the surface.

For the Shackleton Crater area, two Lunar Relay Satellites,forming a relay constellation, are required for continuous relay capability. Three relay satelliteswould provide forredundant

continuous lunar surface to Earth communications capability.While the LCT provides for networked communications in the immediate vicinity of the outpost,a link encompassing a Lunar Rover Vehicle (LRV) and a Lunar Relay Satellite enables longrange (baseline of up to 250 km) excursions from the outpost while maintaining LRV-to-habitatand/or LRV-to-Earth communications links. Table 1 contains a more detailed listing ofanticipated communication support services for a lunar outpost.

Also depicted in Figure 2, is a communications link from a Lunar Relay Satellite to an orbitingspacecraft. Thiscould be theOrion

Crew Exploration Vehicle that provides Earth-to-Lunartransit of crew and supplies. From a communications perspective the CEV is simply anothernetwork asset that can receive, transmit and route communications.

Transport audio, video and data from scientific and engineering instruments

EVA suit communications



EVA audio and visual communications to habitat, LRV, Earth when DTE link exists; toEarth using the LRS when no DTE exists



Human and suit system health monitoring and control (BioMed data)

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.3.1

SURFACE VOICE COMMUNICATIONS

Figure1-35:Surface voice communications and data flows.

Data Flow

Operational Needs

Data Rate

BioMed and Suit Data with 1ECG channel

Nominal

25.2 kbps

BioMed and Suit Data withoutECG

Contingency

1.2 kbps

Nominal Voice (G.729)

Nominal

16.0 kbps

Contingency Voice (G.729, nonetwork overhead)

Contingency

8 kbps

Standard Definition Video(NTSC Quality)

Nominal

1.383 Mbps

High Definition Video (HDTV:720p Quality)

Draft or Desired

7.375 Mbps

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

The following practical concerns are noted for a Lunar Outpost that depends upon wireless RFcommunications:

1)

The lunar topography is complex with craters, mountains and valleys: while externalcommunications in the immediate vicinity of the habitat can be met be a LunarCommunications Tower, longer range excursions will require use of an

internal to habitat the FSF-dominatedcommunications are analogous to RF transmission inside of a

“tin can”, while externalISI-dominated communications will result from multipath due to local terrain variations.Predictive RF path loss models will need to be adapted for the absence of a lunaratmosphere, increased direct solar radiation effects, and

the incorporation of site-specificterrain and surface composition.

3)

Quality of Service (QoS) of the multiple wireless communications links is anticipated tobe an important issue. Why traditional telecommunications engineering can be employedto designthe initial links, once the links are in operation Internet-based QoS may play animportant role is the transiting of prioritized data as the network load increases.

4)

Missions operations require complex modalities when humans are in the loop. Thecoordination of communications between a crew member in a Lunar Rover Vehicle withboth the lunar habitat and potentially multiple terrestrial mission control centers is acomplex communications problem that simply cannot be solved using legacy point-to-point communications links.

5)

Delay tolerant networking is an enabling technology for the Interplanetary Internetenvisioned to provide communications for Lunar Exploration Mission activities. Long-haul, or interplanetary2, communications links (e.g., Earth-to-Moonand Earth-to-Marslinks) must contend with large transmission latencies, potentially high bit-error rates, andasymmetric data rates on the communication channels. Additionally, the availability ofthe communications links (connectivity) is variable due to periodic orbits ofcommunications relay satellite and availability of terrestrial assets, such as the DeepSpace Network (DSN), to participate in a multi-hop communications link. The capabilityto provide in-network storage of voice, video, and data when the network is disconnected–

then transmit when the communications link is re-established can dramatically improvethe transmission efficiency of the data communications system.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.4

IEEE STANDARDS IN SUPPORT OF LUNAR EXPLORATION ACTIVITIES

Based upon the

anticipated environmental and operational requirements associated with a lunaroutpost, it is recommended that the following IEEE standards-based protocols be evaluated forincorporation into the baseline wireless communications system:

The IEEE 802.15 standard encompasses both Bluetooth, which is designated as IEEE802.15.1, and IEEE 802.15.4 compliant devices commonly termed “ZigBee” devices for theZigBee network implementation. Bluetooth and ZigBee (along with 802.11b, 802.11g) terrestrialwireless technology operates in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band asdesignated by the FCC and similar governing bodies in Europe and Asia

including the ITU.

Annex C summarizes the current

IEEE standards group activities for 802.15 as well as 802.11and 802.16. For the 802.15 WPAN, note that 802.15.3 is a high-rate WPAN with the goal of100+ Mbps data rates.

Mid-Range (less than 1 km range):

IEEE 802.11 WLAN (Wireless Local Area Network) for bothad-hoc and infrastructure networks. 802.11bWi-Fi

devices and networks dominate currentterrestrial wireless network communications. Products based on 802.11b have gainedmainstream acceptance as the first wireless networking products with acceptable speeds–

morethat 98% of today’s WLAN infrastructure is based upon 802.11b products3. IEEE 802.11g,provides data rates up to 54 Mbps, and requires backward compatibility with 802.11b devices.802.11a transmits in the 5.7 GHz frequency band. Note that 802.11e specifically incorporatesQoS, 802.11i (approved) addresses the security issues of authentication and encryption, and802.11s (in progress) is working to incorporate mesh (any node can act as arouter) networkinginto the 802.11 standard.

802.16 is also termed “WiMax” and can be used in non line-of-sight environments. Non-LOSmay be critical to ensuring maximum coverage with minimum infrastructure. NLOS radios candramatically reduce the number of repeaters necessary for a large area.

Note that IEEE has built-in QoS, is addressing mobility (important for the LRV) with 802.16eand is addressing co-existence with 802.11 devices in the 2.4 GHz unlicensed frequency band.

The IEEE 802.11, 802.15, and 802.16 standards all directly support the Internet Protocol (IP),address RF co-existence issues with other IEEE protocols from the design phase forward, andimportantly provide a defined upgrade path that includes improved performanceand

backwardscompatibility with pre-existing assets. The use of COTS products that are standards-basedmoves communications protocol development away from smaller research group activities tolarge-scale commercial

space industry, including international space industries.

DRAFT CCSDS REPORT ON INTEROPERABLE WIRELESS NETWORK COMMUNICATIONS

1.5

ASSEMBLY, INTEGRATION AND TEST (AIT) ACTIVITIES

The different AIT applications from ESA and NASA (Wireless Workshop, ESA WirelessDossier)